This invention relates to tack-off machines for automatically removing dust, lint and other particulate contaminants from the surfaces of various types of articles such as a vehicle body prior to priming or painting the surfaces, and more particularly to a contactless cleaning of surfaces of vehicle bodies to prepare them for painting.
To obtain quality painting of exterior surfaces of a vehicle body, dust, lint and other particulate contaminants must be removed from the body surfaces just prior to painting these surfaces. Previously, dust, lint and other particles have been removed by machines with various brushes and manually wiping with a tacky cloth the portions of the body missed by the brushes or by manually wiping the entire body with tacky clothes. These prior approaches are costly, not uniform, and typically leave a significant amount of dust on the body.
A dust removal or tack-off machine with rotary side brushes and at least one rotary top brush which automatically follows the profile of the vehicle body as it moves past the brush to remove dust and other particulate contaminants from the front, hood, roof, and any rear deck in back of the vehicle body is shown in U.S. Pat. No. 4,689,749, the specification of which is specifically incorporated herein by reference. To ensure removal of dust from the front surfaces, the axis of the top brush moves along a path sloping generally upwardly and in the direction of travel of the vehicle body through the machine. The tack off machine senses the location of the vehicle, the style of the vehicle, and moves the elements of the brush assembly into wiping contact with the surface to be painted. Associated ionizing bars direct streams of air onto the brush to ensure that the particles of dust or other contaminants are removed by the brush.
The rotary brush is comprised of a driven tubular shaft and ostrich feathers secured in circumferentially spaced holes in hubs mounted on the tubular shaft. Although ostrich feathers are preferred, bristles of other soft and pliable material, such as synthetic resins, can be used.
While believed suitable for the purposes intended, the use of ostrich feathers has certain problems: wear, breakage of the feather during rotation, expense, and unavailability of feathers. Portions of the feather are prone to break off and may remain on the car surface and be painted over, thus requiring rework. Moreover, ostrich feathers are limited to only certain sizes which will work and thus place a limit the machine geometry. Further, there are problems associated with animal availability and care.
Tack off systems utilizing rotary brushes comprised of long polymeric strands to hit the surface to effect dust removal are known. In such systems, the degree of contact pressure of the rotary brush against the vehicle surface typically must be the same for different vehicle styles. However, during rotation and due to high rotary impact forces, the strand ends can bounce out of the path of the vehicle without properly cleaning the surface, or progressively break off, thus possibly leaving residue on the surface, each situation requiring a longer exposure of the surface vehicle surface to the cleaning brush. A prolonged exposure of the surfaces to the strands will give a "sheen" to the surface, which is objectionable to automobile manufacturers The progressive breakage of the strands is costly both in terms of the replacement cost of the brush as well as in the downtime of the paint line. Additionally, as with the ostrich feathers, broken strand portions may remain on the surface and be painted over.
An object of this invention is to provide a machine which automatically removes essentially all dust and particulate contaminants from the exterior surfaces of a vehicle surface which is to be primed or painted, eliminates contact of the body surfaces, can remove dust from a succession of vehicles and different profiles, is rugged, and of economical manufacture.